Traffic signal system



June 7, 1938. A. F. MARTEL TRAFFIC SIGNAL SYSTEM Filed April 20. 1936 2Sheets-Sheecl FIG.

' INVENTOR; MARTEL ADELARD F.

ATTORNEY June 7, 1938. V MARTEL 7 2,119,593

TRAFFIC SIGNAL SYQSTEM Filed April 20, 1936 2 Sheets-Sheet 2 FIG. 2.

FLA SHER INVENTOR ADELARD F. MARTEL BY M ATTORNEY Patented June 7, 1938TRAFFIC SIGNAL SYSTEM Adelard F. Martel, Burlingame, C'alif., assignorof one-half to George W.

Calif.

Gates, Burlingame,

Application April 20, 1936, Serial No. 75,357

1 Claim.

This invention relates to improvements in trafflc signal systems andmore particularly to combined control and timer apparatus for signalsystems put into operation by a trafic trip switch buried in the trafiiclane. The present signal system is particularly useful for intersectionsof main highways and less travelled lateral cross roads.

Among the objects of the invention is to provide simple and reliablecontrol means for oper ating the traffic signals to clear the right ofway for a predetermined period when a vehicle depresses the trip switchburied in the crossroad trafiic lane.

Another object is to enable an uninterrupted flow of trafiic along thehighway except when a vehicle approaches the intersection from thecrossroad.

. Another object is to provide for alternate timed stop and go signalson the highway when a succession of vehicles are travelling on thecrossroad.

Another object is to conserve the consumption of current at night whenthe trafiic is light while 35 still providing for adequate trafiicsignalling.

Other objects and advantages appear as the description progresses.

In this specification and the accompanying drawings the invention isdisclosed in its preferred form. However, it is to be understood that itis not limited to this form because it may be embodied in other formswithin the purview of the claims following the description.

In the two sheets of drawings:

Fig. 1 is a side elevation of the control box showing the control andtimer unit.

Fig. 2 is a schematic diagram of the electrical circuits included in thesystem.

In detail the construction illustrated in the drawings, referring moreparticularly to Fig. 2

comprises the tripper l buried in the pavement of the lateral road andis operable by the wheels of vehicles passing thereover. It is of thegeneral type illustrated and described in detail in my Patent #1,962,451entitled Trafiic signal con trols. The tripper is adapted to close theswitch 2 which is interposed in an electrical circuit consisting of thesource of electromotive force 3, the

conductors 4 and 5, the solenoid 6, and the conductors 1, 8, and 9leading back to the current source 3.

The lever I0 is pivoted at H on the base 52 within the control box l3.The ferrous core i4 engages the lever I0 and extends into the sole- 5'5noid 6. The solenoid 6 is mounted on the bracket 15 fixed on thestandard I6 extending upward from the base l2.

The lever Ill has the non' conducting block I! thereon with the bus-barsi8 and I9 fixed therein. The contacts 2ll-20 and 2I-2l are mounted 5 onthe insulating panel 22 on the bracket I5 and are adapted to be engagedby the bus-bars i8 and I9 when the solenoid 6 is energized. The contacts2l2l complete the circuit of the motor 23 which includes the conductors9, 8, and 24 leadin ing from the current source 3 to the contacts, theconductor 25 connecting the contacts 2! to the motor, and the conductor26 which leads back to the current source.

The motor 23 is mounted on the support 2! on i=5 inoperative position bythe roller 38 on the disk "25 32. The spring 39 urges the lever 36toward the operative position. The con-conducting arm 43 is pivoted onthe lever 36 at M and has the busbar 42 set therein opposite thecontacts 4343. These contacts are mounted on the insulating 3D block 44fixed on the bracket extension 45 on the standard 16.

The movement of the lever 35 is transmitted to the arm 49 by the pin 46operating in the arcuv ate slot 41. The spring 48 resiliently engages 35one end of the slot 41 against the pin 46. The assembly operates toproduce a snap switch action to avoid arcing when the bus-bar 42 isdisengaged from the contacts 43. When the lever 36 is operated todisengage the bus-bar from the contacts, '40 the friction between thesespring contacts 43 and the bus-bar causes the bus-bar to remain inengagement with the contacts against the tension of the spring 48awhichurges it therefrom. As the movement of the lever 36 progresses, the pin'45 46 arrivesat the end of the arcuate slot 41. The continued movementof the lever 36 then forces the bus-bar 42 outward from the contacts 43.When the bus-bar 42 is once released from the contacts, the spring 48snaps it away therefrom 5 0 in the manner of the usual snap switch.

The contacts 4343 are connected in parallel with the contacts 2 I2l andserve as an auxiliary motor switch in the operation of the system aslater described.

3|. in the circuit of the solenoid'6 between the conclear the revolvingroller 38. I V

The substantially semicircular lever surbase 21. v

The lever 5| has the cam 54 which is adapted to be engaged by therevolving roller 38 to swing the lever 5| into its secondary position.The cam 55 is similarly adapted to cooperate with the roller 38 torestore the lever 5| to its original position. The cam 55 is secured tothe lever 5| by the screw 56. Interspaced screw holes 51 are provided inthe lever 5| so that the position of the cam 55 can be moved to adjustthe timing of f the two phases of the signal operation.

The non-conducting arms 58 and 59 are'pivo ted on the ends ofv the lever5| at 69 and 6|. The pin andslot' connections 62 and 63 and the .springs64 and 65 provide a'resilient cooperation between the lever 5| and thearms 58 and 59 similar to that previously set forth in describing thesnap action of the arm 49 on the lever 36.

The bus-bars 66 and 61 set in the arm 58 cooperate with the contacts69-68 and 69-69 on the insulating block I0. This block is fixed on thelug 3| extending laterally from the standard The switch contacts 69-68are interposed ductors I and 8. 7

The conventional signals H-I-I are placed at the side of. the mainhighway near the intersection. The signals C-C' are similarly mounted onthecross road. The signals are provided with the usual green, amber, andred lamps or other conventional indicia for regulating traffic,

The green lamps II, I2 in the highway signals and the red lamps 13, I4in the cross road signals are in an electrical circuit including thecurrent source 3, the conductors 9 and 8, the switch contacts 69-69, theconductor I6 leading to the lamps and the conductor II leading back tothe source 3. The amber lamps '18, I9, 80, SI of all of the signals'arein a circuit controlled by the switch contactsZIi-ZU previouslydescribed. The contacts are connected to the current source 3 by "theconductors-9, 8' and to the amber lamps 18 to BI' by the conductor 82.The conductor 11 completes the circuit from the lamps back to the source3. The warning signallamps 84, 85 are connected in parallel with thelamps I8 and BI in, a mesh consisting of the conductors 86, 81, 88.These lamps are placed some distance along the highway .from theintersection to forewarn the approaching motorists. The thermal flasherswitch 89 may be interposed in the circuit of the lamps 84, 85 toincrease their effectiveness.

The circuit including the red lamps 99, 9| on the highway and the greenlamps 92, 93 on the crossroad is controlled by the'switch contacts94-94. The non-conducting arm 59 has the bus-bar 95 thereon forcooperation with the contacts 94-94; The contacts 99 are connected tothe current source 3 by the conductors 9, 8 and to the signal lamps bythe conductor 96." The conductor 11 connects the lamps back to thesource 3 to complete the circuit.

The trafficbell 98 is placed at the intersection to direct attention tochanges inthe visual traf- V The pin fic signals. It is interposed in acircuit controlled by the non-burning contacts 99-99 on the resilientmetal strips I09, IllI which are mounted on the insulating blocklfi. Thelever I92 is pivoted on the block I0 and has the roller I93 impinging onthe strip I99. The cam I94 on the lever 5| engages the lever I92 and isarranged to swing this lever to close the contacts 98-9 9. When thelever 5| is swung from one of its operative positions to the other, aslater described, the cam Iii i operates the lever I02 to close thecontacts 99. The time the contacts 99 are closed is brief. Its

duration depends upon the time required for the roller 39 to operate thecams 54 and 55 to swing the lever 5| between its two operativepositions. The contacts are supplied with current from the source'3through the conductors 9, 8 and are con- I nected to the trafficbell98'by the conductor I95. The conductors I66, I'I lead back to thesource.

A modified control mechanism is provided for signaling during the hoursof light traffic atnight. The'modifiedcontrol and timer-is similar,except in details, to that above described. The same reference numeralswith the addition of the prime character are used to indicate similarparts in the modified structure. The night signal control can be mountedin the same control box I3.. In

the night control, the contacts 69-59 and the bus-bar 6! are omitted.This maintains the green lamps II, IE- on the-highway and the red lampsI3, I4 on the crossroad unlighted. The volume of traflic during certainhours does not warrant the expenditure ofcurrent to maintain the signalscontinuously illuminated. The contacts 99-99' controlling the trafficbell 98 can be similarly omitted in residential districts where it isdesirable to preserve quiet at night. The disk 32 is driven at a greaterspeed than the disk 32 so as to provide for a more rapid sequence ofsignals than is possible with the more congested traflic in daytime;

The time switch I01 selectively governs the operation of the day andnight control mechanisms.

The switch I6? either connects the conductor 9 to theconductor 8 whichfeeds all of the switch contacts in the day control or it connects theconductor 9 to the conductor 8 which is similarly in circuit with thenight control. The times of the.

operation of the switch can be regulated by the manual'knob I98 (seeFig. 1).

The manual switch I 99 is wired in parallel with. J

the time switch I9! and enables an officer to continue the operation ofthe day control at night when necessary. The switch H9 is provided tocut out the time switch I01 when the'manual switch is being used.

The signal system operates substantially as follows: Assuming the timeswitch I9! is in polamps remain illuminated except when a vehicleapproaches from the crossroad thus maintaining the main highwayunobstructed as long as no vehicle enters the intersection from thecrossroad.

The driver of a vehicle approaching the intersection from the crossroadis directed 'by suitable road signs to drive over the tripper i. Thiscloses the switch 2 and energizes the solenoid 6 through the conductorsl, 5 and I and the switch contacts 88-68. The core l4 attracted into thesolenoid swings the lever Ill and closes the contacts 2826 and 2 I-2I.The core l4 remains in this operative position even after the solenoid 6is deenergized by the automatic opening of the switch 2 after thevehicle haspassed over the tripper i.. The switch contacts 20-40complete the previously traced circuit of the amber lamps l8, 19, 80, 8!and the flashing signal lamps 8G, thus warning the oncoming traflic ofthe impending change of signals.

The switch contacts 2i2l complete the circuit also previously traced ofthe motor 23. The motor then drives the disk 32 at the predeterminedconstant speed. The revolution of the roller 38 on the disk 32 carriesit beyond the end of the switch lever 36. The spring 39 then swings thelever 38 downward to engage the bus-bar 42 in the contacts 4343. Theseclosed contacts maintain the motor circuit closed after the contacts2l-2i have been opened by the restoration of the lever H1.

The continued revolution of the roller 38 after a predetermined intervalcarries it into engagement with the cam 5-! and swings the lever 54 onits pivot 52. This engages the bus-bar in the contacts 94-9t. Thiscloses the circuit previously described and illuminates the red lampsS9, 9! in the highway signal and the green lamps 92, 93 in the crossroadsignal.

The bus-bars 66 and 6'! simultaneously snap out of engagement with thecontacts 6868 and ESQ-59. The breaking of the contacts 69 opens thecircuit of the green lamps 11,12 on the arterial and the red lamps i3, Mon the lateral. The opening of the contacts 68-68 opens the circuit ofthe tripper switch 2 and the solenoid 6. This enables the vehicles onthe crossroad to pass over the tripper when the green light is showingwithout energizing the solenoid 6.

The movement of the lever 5| produced by the roller 38 causes the camI04 to swing the roller I63 on the lever I02 against the resilient stripH30 to close the contacts 9999. This rings the trafiic bell 98 throughthe circuit previously traced at the time the signals are changing.

While the lever 5| is being moved by the roller 38 the pin 5!) engagesthe upper end 19 of the lever H! and restores it to the inactiveposition shown in Fig. 1. This opens the contacts 2020, 2i-2I. Theopening of the contacts 2fl2!l breaks the circuit previously describedof the amber lamps 18 to BI and the warning signal lamps 84, 35. Thecontacts 2 l-Zl are interposed in the circuit of the motor 23 aspreviously described. However, the operation of the motor is continueddue to the closed switcl'i contacts 45-43 which are wired in parallelwith the contacts 2l--2 l After a predetermined time interval, theroller 38 revolves into engagement with the cam 55 and restores thelever 5! to its original position. This opens the contacts 9494 andopens the circuit of the red lamps 9!], 9! on the arterial and the greenlamps on the lateral. The closing of the contacts 6969 illuminates thegreen lamps H, 12 on the highway and the red lamps 13, 14 on thecrossroad. Closing the contacts 68 again completes the circuit of thesolenoid 6 so that the next vehicle passing over the tripper I willenergize the solenoid.

After the roller has continued to revolve for another predeterminedinterval, it comes into operative engagement with the lever 36., Thelever is thus swung on its pivot 37 and snaps the bus-bar 42 out ofengagement with the contacts 43-43. If the tripper has not been operatedby a vehicle in the lateral passing thereover, the opening of thecontacts 4343 halts the motor 23 leaving the control unit in readinessfor another cycle of operation initiated by a vehicle passing over thetimer.

If the tripper has been operated during the latter phase of theoperation of the control and timer, the energization of the solenoid 6closes the contacts 2I2i. The operation of the lever 36 by the roller 38disengaging the bus-bar 42 from the contacts 33- 33 thus will not haltthe operation of the motor because of the closed contacts ZI-Zl. Thecontrol unit then, without pausing, will pass through another cycle ofoperation.

At a predetermined time, the time switch I01 reverses itself opening thecircuits through the wire 9 and closing the circuits fed by the wire 8'.This places the night control unit into operation.

The operation of this control is substantially It is desirable 1 similarto that above described. to drive the disk 32 at a greater speed thanthe disk 32 to permit more rapid control of a lighter volume of traffic.The contacts 5464 being omitted, the green lamps H, 72 on the highwayand the red lamps 73, M on the crossroad are not illuminated.

Having thus described this invention, what is claimed and desired to besecured by Letters Patent is: V V

In a trafiic signalling system, a motor circuit including an electricmotor, and two switches in parallel for energizing said motor wheneither is closed, a disc driven by said motor, lugs on said disc spacedin the direction of rotation of the disc, means operated by one lug toopen one of said switches when engaged by the lug, a lever in the pathof the second of said'lugs and movable to switch opening and switchclosing position for operating the second of said switches, meansoperated by trafiic for moving said lever to switch closing positionwhereby the motor is energized and the disc rotated and the first lugmoved away from said one switch opening position, means to thereuponclose said one switch, the second lug thereafter moving said lever toopen the second switch, an arcuate control element having a cam thereonin the path of the first lug to shift the position of said controlelement upon engagement by said first lug, a second camcircumferentially adjustable on said control element, and adapted torestore said control element to its original position upon engagement bysaid first lug, trafiic signals, and means to display one group ofsignals when the control element is in one position, and a second groupwhen the control element is in the original position.

' ADELARD F. MARTEL.

